Unit 4 - Weight Flashcards
What are the 12 causes of obesity?
- More calories
- Bigger portions
- Fast food
- Hunger and satiety
- Physical inactivity
- Passive entertainment
- Prenatal factors
- Developmental factors
- Genetics
- Emotional influences
- Social networks
- Social determinants
Explain how bigger portions cause obesity
The size of many popular restaurants and packaged foods has increased two to five times during the past 20 years. Studies also show that with larger portion sizes people eat many more calories than they would otherwise
Explain how fast food causes obesity
People who eat frequently at fast-food restaurants gain more weight and develop metabolic abnormalities that increase their risk of Type 2 Diabetes.
Explain how hunger and satiety causes obesity
In addition to genes, there are other signals that can influence our hunger.
- Hormones, including insulin and stress-related epinephrine (adrenaline), may stimulate or suppress hunger.
- The size of our fat cells may also affect how hungry we feel.
- Appetite can also be a learned phenomenon. We learn to avoid hunger by eating a certain amount of food at certain times of the day. We stop eating when we feel satisfied or have reached satiety.
- Appetite is easily led into temptation. Creamy, buttery, or greasy foods may override our natural feeling of fullness and encourage overeating, causing internal changes that increase appetite and, consequently, our weight. .
Explain how passive entertainment causes obesity
Television, computers, iPads, and all things “technology” may increase weight in several ways. First, using technology takes up time that otherwise might be spent in physical activities. Secondly, it increases food intake since people tend to eat more while watching TV or sitting at a computer
Explain how prenatal factors can cause obesity
A woman’s weight before conception and weight gain during pregnancy influences her child’s weight. A substantial number of children are prone to gaining weight because their mothers developed gestational diabetes during their pregnancies. Children born to obese women are more than twice as likely to become overweight.
Explain how developmental factors cause obesity
Some obese people have a high number of fat cells, others have large fat cells, and the most severely obese have both a high number and large fat cells.
What is Hyperplasia?
Hyperplasia describes a point in time where the number of fat cells increases. Usually this only occurs during infancy and puberty. However, it does appear that fat cells can also increase in numbers when a person consumes more calories than they burn on a regular basis over a period of time.
What is Hypertrophy?
Hypertrophy is a process whereby the fat cells increase in size and this can happen at any time in life if calories taken in are greater than caloric expenditure, or calories going out.
Explain how genetics can cause obesity
The GAD2 gene signals the brain to tell us to eat. If this gene is defective or malfunctions, it could contribute to weight problems by signalling us to eat more often than we need to.
The Ob gene, which interrupts our body’s built-in “feel full” system, might be the gene that allows us to eat a greater amount of food than we need to survive. Abnormalities in many genes create a predisposition to weight gain and obesity
Explain how Emotional influences can cause obesity
While psychological problems such as irritability, depression, and anxiety are more likely to be the result of obesity, not the cause, some people who are emotionally fragile do cope by overeating
Explain how social networks can cause obesity
Friends may have a significant effect on a person’s risk of obesity. it may be that friends alter your perception of fatness: when a close friend is obese, obesity might seem normal and acceptable
Explain how social detriments can cause obesity
In affluent countries, more people in lower socioeconomic classes tend to be obese. For reasons unknown, those in the upper classes, who can afford as much food as they want, tend to be leaner. Education may be a factor
How do you calculate your BMI?
by dividing your weight in kilograms by your height in metres, squared.
What is WHR and how do you determine it?
Waist to hip ratio. divide your waist circumference by your hip circumference
What are the two types of fat in the body?
Essential fat and storage fat
What is essential fat?
makes up about 3 to 7 percent of body fat in men and 10 to 15 percent in women and helps with physiological function such as nerve conduction
What is storage fat?
for healthy adults is somewhere between 5 and 25 percent. It helps keep us warm by insulating our bodies
What is the overall ideal body fat percentage?
for men range from 7 to 25 percent and for women from 16 to 35 percent.
What are the five methods for assessing body composition?
- Skinfold fat measurement
- Bioelectrical impedance analysis
- Dual-energy X-ray absorptiometry (DXA)
- Hydrostatic (underwater) weighing
- Air displacement plethysmography
What is the skin-fold fat measurement assessment?
A calliper is used to measure the amount of skinfold. Various sites on the body are measured, depending on different skinfold tests. Equations determine body fat percentage.
What is the bioelectrical impedance analysis assessment?
It uses a BIA analyzer where a low-level electrical current is passed through the body and the impedance or opposition to the flow of current is measured. The resistance to current flow will be greater in individuals with large amounts of body fat because adipose tissue is a poor conductor of electrical current due to its relatively low water content.
What is the DXA?
X-rays are used to quantify the skeletal and soft-tissue components of body mass.
What is the hydrostatic (underwater) weighing assessment?
it measures the weight of displaced fluid. Muscle has a higher density than water, and fat has a lower density. Thus fat people tend to displace less water than lean people.
